1. Field
The invention relates to buoyant water powered device for producing electricity or other mechanical work in areas of flowing water.
2. Information
This invention relates to a device that is designed to capture energy from existing currents of water and is particularly designed to operate while floating in-stream.
One of this planet's most common and readily available source of renewable energy is moving water. The power of Hydro kinetic energy is well known and well documented. It is abundant and is found in the vast quantities in every stream, river or other moving bodies of water. Its use and utilization is a function of economic and ecological constraints.
The most familiar methods for the utilization of this energy require dams, impounds or major civil works to contain and redirect the current. Making those methods inappropriate, or impractical for the majority, if not substantially all existing currents, for economic and ecological reasons. Therefore if this vast resource is to be accessed effectively and efficiently, existing currents must be utilized, while minimizing environmental and economic impacts.
A more economical and environmentally sensitive means for utilizing and capturing kinetic energy from existing currents are generally called free flow or in-stream hydropower. In many instances these in-stream devices require physical support from a structure, which is placed or attached to the river or stream's bed, or bank. This increases costs, perhaps disrupting navigation and the environment. Therefore are not viable options in many locations.
It is, therefore, a principal objective of this invention to substantially eliminate the need for the construction of any such civil works by positioning the device on the surface without fixed support structures. By floating, the invention substantially eliminates the need for such structures.
In other instances the water powered device is positioned in the current, through placement or attachment to a floating component, to provide support. These separate floating components add cost, complexity, and inefficiency. Because these floating components are subjected to the forces of the current they must effectively resist and dissipate that kinetic energy to remain in the desired position.
It is another object of this device to increase efficiency and effectiveness of converting the current's kinetic energy into usable power by integrating the required buoyancy into the device. Therefore reducing drag on the device, increasing its efficiency, and increasing the kinetic energy available to the turbine. Some of these floating water powered devices, integrate a floating component into the device. This too increases drag upon the device reducing efficiency.
Therefore it is another objective of the device to integrate the required buoyancy into the functional parts of the device to reduce drag and increase efficiency.
Many water-powered devices have employed propellers or water wheels that are substantially fully submerged in the water. Such devices must be positioned with their axis of rotation extending parallel to the direction of flow of the water. This is not a viable alternative in many circumstances. Requiring more depth of the current, and involving navigational and environmental concerns with debris and aquatic life providing a risk to the device and aquatic life alike.
It is a further objective of this invention to provide a buoyant water powered device that will not require to be completely submerged within the water.
All in-stream water powered devices must be held in a fixed position in the current to operate. In many cases theses devices may have multiple connections serving individual or multiple functions. Each additional connection requires additional effort to construct, install and maintain. Each additional connection increases the risk of entanglement with debris and aquatic life.
It is, therefore, a still further objective of this invention to provide an improved tether that can integrate multiple functionality with support for positioning the device, in an integrated single tether, serving as a single point of physical connection.
For maximum efficiency and water powered device must maintain its position relative to the current. In many alternatives this may include a support structure, or in the case of floating devices rudders, vanes and other single purpose additions.
It is another objective of this device to integrate features that maintained its position was so that the turbine's rotation is about an axis that is perpendicular to the current. These features will additionally contribute to the turbine's efficiency, debris avoidance and structural functionally.
In most in-stream surface based water powered devices are based upon the undershot water wheel and limited to hydro-kinetic energy of the current.
It is another objective of this device to create hydro static pressure and utilize it in addition to the current's hydro-kinetic energy, by the positioning of turbine, blades and the integration of the other parts.
3. Prior Art
By their nature, water powered devices must be positioned relative to the resource upon which they rely. Many are located or fixed to a permanent support structure such as a dam, pier, or foundation. Others are mounted to the ground or the bottom of the stream or river bed. One subset of water powered devices maintains their desired position by floating on the surface of the current or water source. This subset of floating surface-mounted, water powered devices encompass those devices that are attached to or mounted upon flotation components that contribute little or no functional value to the water-powered device, aside from providing support. Another set of floating water-powered devices integrate the flotation component into the device itself as, in the case of the device described in U.S Pat. No. 4,872,805. These articulated buoyant members contribute drag on the device, and do not contribute to the device's efficiency in capturing the kinetic energy delivered to the water powered device.
Some devices such as in another embodiment of U.S. Pat. No. 4,872,805 use the hydro dynamic force of the current to assist in maintaining the device's position, relative to the surface of the water. This too, fails to effectively utilize efficiently the Hydro kinetic energy placed upon, and delivered to, the device.
Another type of floating water powered device as disclosed in U.S. Pat. No. 7,042,113, a generator is placed in the drum that is rotated by moving water. This device requires multiple attachments to both sides of the drum at its axes and is affixed to a permanent structure. The placement of the generator within the drum of the water wheel, limits the flexibility of adjusting the device for various current conditions, and requires multiple attachments that increase the device's risk of damage or entanglement in debris. This is why the invention attaches the tether to a single point on the driven component at the midpoint of the rotor.
Existing buoyant or floating water powered devices such as water wheels or turbines, are of a type called undershot water wheels. These devices use the principle of impulse power in which only the kinetic power, or the strength of the current, is utilized. This invention the subject of this patent utilizes not only impulse power but also hydrostatic pressure. Hydrostatic pressure has been utilized with fixed rotary hydraulic pressure machines, with dams or other form of water retention. Hydrostatic Pressure results from higher water surface levels upstream to the turbine versus downstream. Because of this invention's distribution of buoyancy to the rotor, it allows for maximum force to develop over its' entire width of the turbine enabling a disparity in water level between the upstream and downstream side of the turbine. The invention's implementation of a single rotor with the major points of dissipation of the current's excess kinetic energy is limited to the rotor ends increasing the disparity of the water level and pressure between the upstream and downstream sides of the rotor. The rotor does have a gap for the attachment of the tether to the driven component, but it is or minimized size and with a ridge extending through the gap, the effect is effectively eliminated.